Added ErrorBars Element

holoviews/element/chart.py

@@ -239,6 +239,39 @@ def progressive(self):
 
 
 
+class ErrorBars(Chart):
+    """
+    ErrorBars is a Chart Element type representing any number of
+    errorbars situated in a 2D space. The errors must be supplied
+    as an Nx3 or Nx4 array representing the x/y-positions and
+    either the symmetric error or assymetric errors respectively.
+    Internally the data is always held as an Nx4 array with the
+    lower and upper bounds.
+    """
+
+    group = param.String(default='ErrorBars', doc="""
+        A string describing the quantitity measured by the ErrorBars
+        object.""")
+
+    key_dimensions = param.List(default=[Dimension('x'), Dimension('y')],
+                                bounds=(2, 2), constant=True, doc="""
+        The Dimensions corresponding to the x- and y-positions of
+        the error bars.""")
+
+    value_dimensions = param.List(default=[Dimension('lerror'), Dimension('uerror')],
+                                  bounds=(2,2), constant=True)
+
+    def __init__(self, data, **params):
+        data = list(data)
+        data = self._null_value if (data is None) or (len(data) == 0) else data
+        if len(data) and not isinstance(data, np.ndarray):
+            data = np.array(data)
+        if data.shape[1] == 3:
+            data = np.hstack([data, np.atleast_2d(data[:, 2]).T])
+        super(ErrorBars, self).__init__(data, **params)
+
+
+
 class Bars(NdElement):
     """
     Bars is an Element type, representing a number of stacked and

holoviews/plotting/__init__.py

@@ -299,6 +299,7 @@ def set_style(key):
 # Charts
 Store.options.Curve = Options('style', color=Cycle(), linewidth=2)
 Store.options.Scatter = Options('style', color=Cycle(), marker='o')
+Store.options.ErrorBars = Options('style', ecolor='k')
 Store.options.Bars = Options('style', ec='k', color=Cycle())
 Store.options.Histogram = Options('style', ec='k', fc=Cycle())
 Store.options.Points = Options('style', color=Cycle(), marker='o')

holoviews/plotting/chart.py

@@ -10,7 +10,7 @@
 from ..core.options import Store
 from ..core import OrderedDict, NdMapping, ViewableElement, CompositeOverlay, HoloMap
 from ..core.util import match_spec
-from ..element import Scatter, Curve, Histogram, Bars, Points, Raster, VectorField
+from ..element import Scatter, Curve, Histogram, Bars, Points, Raster, VectorField, ErrorBars
 from .element import ElementPlot
 from .plot import Plot
 
@@ -144,6 +144,72 @@ def update_handles(self, axis, view, key, ranges=None):
 
 
 
+
+class ErrorPlot(ChartPlot):
+    """
+    ErrorPlot plots the ErrorBar Element type and supporting
+    both horizontal and vertical error bars via the vertical
+    plot option.
+    """
+
+    vertical = param.Boolean(default=False, doc="""
+       Whether to draw horizontal or vertical error bars.""")
+
+    style_opts = ['ecolor', 'elinewidth', 'capsize', 'capthick',
+                  'barsabove', 'lolims', 'uplims', 'xlolims',
+                  'errorevery', 'xuplims', 'alpha', 'linestyle',
+                  'linewidth', 'markeredgecolor', 'markeredgewidth',
+                  'markerfacecolor', 'markersize', 'solid_capstyle',
+                  'solid_joinstyle', 'dashes', 'color']
+
+
+    def __call__(self, ranges=None):
+        element = self.map.last
+        axis = self.handles['axis']
+        key = self.keys[-1]
+
+        ranges = self.compute_ranges(self.map, key, ranges)
+        ranges = match_spec(element, ranges)
+
+        error_kwargs = dict(self.style[self.cyclic_index], fmt='none',
+                            zorder=self.zorder)
+        kwarg = 'xerr' if self.vertical else 'yerr'
+        error_kwargs[kwarg] = element.data[:, 2:4].T
+        _, (bottoms, tops), verts = axis.errorbar(element.data[:, 0],
+                                                  element.data[:, 1],
+                                                  **error_kwargs)
+        self.handles['bottoms'] = bottoms
+        self.handles['tops'] = tops
+        self.handles['verts'] = verts[0]
+
+        return self._finalize_axis(self.keys[-1], ranges=ranges)
+
+
+    def update_handles(self, axis, view, key, ranges=None):
+        data = view.data
+        bottoms = self.handles['bottoms']
+        tops = self.handles['tops']
+        verts = self.handles['verts']
+        paths = verts.get_paths()
+        if self.vertical:
+            bdata = data[:, 0] - data[:, 2]
+            tdata = data[:, 0] + data[:, 3]
+            tops.set_xdata(bdata)
+            bottoms.set_xdata(tdata)
+            for i, path in enumerate(paths):
+                path.vertices = np.array([[bdata[i], data[i, 1]],
+                                          [tdata[i], data[i, 1]]])
+        else:
+            bdata = data[:, 1] - data[:, 2]
+            tdata = data[:, 1] + data[:, 3]
+            bottoms.set_ydata(bdata)
+            tops.set_ydata(tdata)
+            for i, path in enumerate(paths):
+                path.vertices = np.array([[data[i, 0], bdata[i]],
+                                          [data[i, 0], tdata[i]]])
+
+
+
 class HistogramPlot(ChartPlot):
     """
     HistogramPlot can plot DataHistograms and ViewMaps of
@@ -885,6 +951,7 @@ def update_handles(self, axis, element, key, ranges=None):
                        Bars: BarPlot,
                        Histogram: HistogramPlot,
                        Points: PointPlot,
-                       VectorField: VectorFieldPlot})
+                       VectorField: VectorFieldPlot,
+                       ErrorBars: ErrorPlot})
 
 Plot.sideplots.update({Histogram: SideHistogramPlot})